what is crankcase fluid

Crankcase fluid is just a fancy term for engine oil in most ATVs. The crankcase holds the oil that lubricates the bottom end. If you have a separate filler, it's likely a dual-chamber system where one side is the transmission oil and the other is engine oil. Check your manual for the specific fill port.

Not always the same. On some older utility quads, the crankcase and transmission share oil, but on many sport models they're separate. You need to verify which fluid goes where. Putting gear oil in the crankcase will wreck your engine. I'd look up a diagram for your model.

Polaris often uses a single fill for both engine and transmission, but if you see two caps, one is likely for the gearbox. Crankcase fluid literally means the oil that lives in the crankcase. If that's a separate compartment from the transmission, then it's just engine oil. Check your dipstick markings.

I have a 500 same year. The cap on the left side is engine oil, right side is transmission. Crankcase fluid would be the engine oil. The transmission uses ATV gear oil. Don't mix them up or you'll have shifting problems. I've done that once—learned the hard way.

Actually, on that Polaris, the engine and transmission share the same oil bath. The crankcase is just the housing. If you see a separate fill cap lower down, that might be for the front differential or something. Post a photo. But generally, crankcase fluid = engine oil.

To simplify: the crankcase is the lower part of the engine where the crankshaft spins. The fluid in there is your engine oil. If there's a separate cap, it might be for checking the level, not adding. Always use the recommended viscosity. For your 500, 10W-40 is typical.

I think some folks are mixing up terms. Many ATVs have a wet clutch that shares oil with the engine. That oil is still crankcase fluid. But if there's a second cap, it could be for the final drive. Don't assume. Check the owner's manual or ask a dealer.

Stop overcomplicating. Crankcase fluid is just engine oil. Your Polaris 500 has a single sump. The second cap might be a breather or level check. If you're still unsure, drain a little and see what comes out. If it's black and smells like gas, it's oil.

I disagree with the last reply. Not all Polaris 500s have a shared sump. Some years had separate transmission oil. The crankcase is specifically the engine's lower end. If you fill the crankcase with gear oil meant for the transmission, you'll damage bearings and rings. Been there.

Best bet: go to the Polaris forums and search 'crankcase fluid 500.' There's a sticky post that shows exactly which fluid goes where. Also, if your owner's manual has a 'fluids' section, it'll list the capacities. Crankcase fluid is engine oil—period. The other cap is likely transmission.

Don't listen to anyone guessing. I have the same quad and I accidentally put gear oil in the crankcase years ago. Had to flush it three times. The crankcase fill is the one with the dipstick. The other cap near the rear is for gear oil. Pretty sure your separate cap is the transmission.

I'm a mechanic. Crankcase fluid refers to the oil that circulates through the crankcase to lubricate the pistons and bearings. On most ATVs, that's the same as engine oil. But Polaris has redesigned things over the years. Confirm on your specific VIN. If you're still lost, call a dealership.

Could also be that the 'crankcase fluid' cap is actually for the oil tank if it's a dry-sump system. Some high-performance ATVs have remote oil tanks. Check if your Polaris has a dry sump—unlikely on a 500, but possible. The filler cap might be for the oil reservoir, not the crankcase itself.

Why not just look at the cap? It usually has a symbol or says 'engine oil' or 'gear oil.' If it's unmarked, trace the hose. If it goes to the engine block, it's crankcase. If it goes to the transmission case, it's gear oil. Simple. No need to overthink.

I recall that on the Sportsman 500, the two fill caps are both for engine oil—one is a level check, the other is the fill port. But that would be weird. Honestly, I'd just use the one that says 'oil' and ignore the other. Crankcase fluid is engine oil. Full stop.

Partial disagreement: on some models, the 'crankcase' is actually the gearbox housing that holds transmission fluid. The engine uses a separate system. You absolutely must verify. A common mistake is putting 80W-90 gear oil in the engine. It will smoke and seize. Don't guess—google a diagram.

I'd recommend draining both and seeing what you get. If one has silver shavings, that's transmission. If it's just dark sludge, it's engine oil. Then refill accordingly. But the term 'crankcase fluid' is ambiguous. In your manual, look for 'engine oil capacity' and 'transmission oil capacity.'

If you're still paranoid, just use AMSOIL or Rotella T6 for the crankcase if it's engine oil. That's what I run in my 500. No issues. But again, confirm the other cap. Some people run the same oil in both, but I prefer using gear oil in the transmission for better protection.

Okay, everyone chill. Crankcase fluid is engine oil. The other cap—if it's near the rear—is for the gearbox. The gearbox uses a heavier oil. If you accidentally mix, it's not catastrophic if you drain soon. But do it right. Check YouTube for 'Sportsman 500 oil change.'

I think the confusion is that 'crankcase' is sometimes used interchangeably with 'engine' in older ATVs. On your 2007, it's likely a shared sump. The separate cap might be a vent or a drain. Best to post a pic on a forum. But in short, crankcase fluid = engine oil.